The subject invention relates to automatic gain control (AGC) circuitry and, more particularly, to an AGC circuit having both analog and digital gain adjustment portions. The subject invention finds particular utility in digital data modem implementations.
In such modem implementations it would be desirable to utilize a coarse analog gain control section to bring the gain within the range of an anlog to digital converter circuit, while having a digital gain control circuit at the output of the analog to digital converter to provide a steady, precise digital level for the modem circuitry to utilize. However, provision of such an automatic gain control circuit has presented the problem of how to establish cooperation among simultaneously operative analog and digital gain control sections in order to achieve smooth and rapid progression to the gain level desired.